IBD classification needs an upgrade

Review reflects complexity of IBD and challenges of change

The review is important at this time because of the growing recognition that IBD, while traditionally categorized as either UC or CD, is most likely composed of a range of heterogeneous conditions involving inflammation of the gastrointestinal tract, Jatin Roper, MD, of Duke University in Durham, N.C., said in an interview.

“Evidence that our current classification of IBD is suboptimal comes from both the wide range of clinical phenotypes as well as complexity in genetic markers that are associated with IBD,” he said.  “It is well accepted in the gastroenterology community that IBD is a complex condition; so it is surprising to me that the dichotomy of UC vs. Crohn’s disease has rarely been challenged,” said Dr. Roper. “The authors of this review should be commended for raising the question of whether IBD deserves a more nuanced classification system that reflects the growing recognition of the wide heterogeneity of patient presentations and genetics,” he said.   

“Challenging medical definitions is inherently difficult because patient diagnoses, treatment plans, as well as decades of clinical research have been based on well-accepted disease categories. Another major challenge in reclassification is that the course of IBD can vary greatly over time in the same patient in severity, range, and complexity, and potentially includes many disease subtypes noted by the authors of this review,” he added. “Therefore, I believe that the current system of dividing IBD in UC and CD is here to stay until subtypes based on mechanisms of disease pathogenesis are discovered.

“Additional research is needed to understand the molecular basis of IBD,” Dr. Roper emphasized. “Recent advances in RNA expression and proteomics at the single cell level may reveal distinct cell types or cell functions in tissues from IBD patients that may help us understand clinical phenotype or response to therapy.”

The study received no outside funding. The authors disclosed financial relationships with AbbVie, Biogen, Chiesi, Falk, Ferring, Galapagos, Janssen, MSD, Pfizer, R-Biopharm, Takeda, and Truvion. Dr. Roper had no financial conflicts to disclose.

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*Correction, 4/11/22: An earlier version of this article misstated the Montreal Classification.